PNtalk is a long term project developing a system which combines Petri
nets and Smalltalk in a consistent way by introducing Object Oriented
Petri Nets. The objective of PNtalk is modeling, simulation, and
prototyping systems. Our current focus is higher level of dynamism and
higher level of control over PNtalk features in order to allow
heterogeneous modeling and better interoperability with its
environment. The most important feature is a possibility of replacing
Petri nets by other formalisms in some parts of a model. To achieve
these goals, an open approach proposing appropriate level of control
over selected features of models is adopted. The open implementation of
PNtalk is accomplished by its reflective metalevel architecture.